Interlocking device



June 2, 1925.

J. D. WOOD INTERLOCKING DEVICE Filed June 10, 1922 2 Sheets-Sheet 1 I INVENTOR Jade a6 D. 14 000 WlTNESSES: Zka

ATTORNEY WITNESSES: $.97 (Mm/1W %M J. D. WOOD INTEIIRLOCKING DEVICE Filed June 10, 1922 2 Sheets-Sheet 2 iNVENTOR Jase 05D. Wood v 7 AT'ToRNEY i atented June 2, 1925.

UNITED STATES PATENT OFFICE.

JOSEPH D. WOOD, OF MURRYSVILLE. PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

INTERLOGKING DEVICE.

Application filed June 10, 1922. Serial No. 567,492.

use in connection with electric motors that require a relatively low voltage when being started to bring them up to, and a higher voltage to maintain them at, their normal running speeds.

One obj ect of my invention is to provide a construction wherein the switch that co. trols the low-voitage circuit must be mov to closed position and then completely opened before the switch that controls the high-voltage circuit can be closed and whei in each switch is held against closing mov=- ment while the other switch is in closed position.

Another object of my invention is to provide means whereby the switch that contr:

the high-voltage circuit cannot be moved t closed position except within a limited time after the low-volta e circuit has been opene Various types of apparatus have been designed to automatically provide for the proper sequence or" operation, as between a startin switch and a running, or high-voitage switch, but diliiculty has been expe; enced in designing a structure wherein p vision is made to insure the closing of a running switch before the motor has lost c momentum set up therein through theopen ation of the starting switch.

1 provide a construction wherein the run.- ning switch must be closed, it at all, at substantially the instant that the startingswitch lever reaches its open position, and one wherein the use of springs, with the difiiculties incident thereto, are avoided.

In the accompanying drawings,

Figure 1 is a view, partially in side eleration and partially in section, of appa etus embodying my invention,

2 is a view thereof in rear elevation,

Figs. 3 and 4 are side elevational views showing the positions occupied by certain of the parts at various stages of their move ments, and

Fig. 5 is a sectional View showing the position occupied by certain of the other parts at certain stages of their movements.

My invention is shown as applied to the operating mechanism of a circuit breaker and comprises a bracket 6 secured to a panel 7. A lever 8 is supported in the bracket 6 by a pin 9. and a lever 10 is supported thereon by a pin 11. I will designate the levers 8 and 10 as starting-switch levers and running-switch levers, respectively, the lever 8 being employed to start the motor under low voltage and the lever 10 being employed to impress high voltage on a motor that is not shown.

At its outer end, the lever 8 supports,"

through a pin 14, a lifting rod that controls a switch r circuit breaker, not she The lever 30, through a pin 13. operates lifting rod 16 of another switch or circus breaker, not shown. It will be observed that the pins 14 and 13 extend inwardly for considerable distances.

A casting or interlock member 18. is sus pended from the bracket 6 by a pin 19 and is provided with side portions 20 and 21 that are joined by a web portion 22. The portion 22 is provided with an opening 23 therethrough, and with a latch-engaging portion 220. as shown more clearly in Fig. 5

The side portion 21 the casting 18 is provided with an arcuate slot, one wall 25 of which serves as a camming surface and the other wall of which is provided with an offset portioi' 53 that may engage the pin 14 to restrain upward movement thereof under certain conditions.

The side portion of the casting 18 provided with a cramming surface 28 and a shoulder 29 that are engaged by a pin 13, under predetermined conditions. (Fig.

A latch 31 is pivoted at 32 to the bracket 6 and is provided with an upwardly extend-- ing portion 33. The outer end of the latch 31 serves, when in operative position, to engage the portion 22a of the casting 18.

The levers 8 and 10, the casting 18 and the latch 31 normally occupy the positions illustrated in Figs. 1 and 2, in which position the switches controlled by the levers E; and 10 are in open position. In this posi tion, the pin 3.4 of the lever 8 may move i all;

freely in the slot of the side portion 21 of the casting 18, but the pin 13 of the lever 10 is locked against movement by the shoulder 29 of the side portion 20 (F g. 5).

Upon movement of the lever 8 in .a clockwise direction, to close its switch through the lifting rod 15, the pin 14 is carried upwardly into engagement with the extension 33.01? the latch 31, as shown more clearly 1n F1 s. 3 and 4. This disengages the interloc lring member 18 from the latch 31 and permits such member to swing in a counterclockwise direction by reason of gravity, until the inner wall of a recess 35 (Fig. of the side portion 20 of the casting is in engagement with the pin 13. The upper wall of the recess 35 is of such shape that pressure upwardly by the pin 13 Wlll not tend to move the member 18 to the positlon shown in Fig. 5 and thus permit the latch to fall when the pin 14 is moved away from the extension 33.

V V i i i This movement by the casting 18 carries the camming surface 25 into the path of the in 14 so that, upon a rapid movement 0? the lever 8 in a counter-clockwise direction, a camming enga ement takes place between the pin 14 an the wall 25 suflicient to swing the castin 18 in a clockwise direction past the osition shown in Fig. 5 and release the pin 13 of the lever 10 from engagement with the shoulder 29. In this position, if the lever 10 be moved quickly in a clockwise direction, the pin 13 carried thereby may pass upwardly along the cammin'g surface 28 to close the switch that is controlled by the lifting rod 16. This movement carries the lower end of the interlocking member still further in a clockwise direction and brings the shoulder 26 of the side member 21 into the path of the pin 14 to prevent upward movement of such pin and thus insure that the starting switch which is actuated by the lifting rod 15 cannot be closed until the lever 10 has been moved in a counter-clockwise direction to return the pin 13 and the lifting rod 16'to theirlower, or open, positions. Upon downward movement of the pin 13, the interlock member 18 may swing back, under the action of'gravity, to latched engagement with the latch 31, thus causing the lever 10 to be again latched in retracted position and the lever 8 be again released'for movement to advanced position.

To secure certainty in its operation, the lever 10 is maintained under closing tension while the lever 8 is being retracted, so that it may be snappedto advanced position the instant the'lever 8 has reached its open position. The contour of the engaging surface of the shoulder 26 is such that the upward pressure of the pin 13-does not seriously resist the movement of the casting 18 by the cumming action above described.

The latch 31 also serves to hold the member 18 against movement, through force exerted by the in 13 against the rounded surface of the s oulder 26 in case an attempt be made to operate the lever 10.0ut of its turn.

It will be observed that the latch 31 is of such contour that it permits the lug 22a to pass thereover freely, when moved rapidly in a clockwise dlrection, but will catch the lug 22a when the castin 18 swings back, in a counter-clockwise irection.

From the foregoing, it will be seen that the casting 18 is of such form that it prevents either of the switch levers 8 and 10 from being moved to closed position while the other lever is closed and that the lever 10 cannot be closed until the lever 8- has been first advanced and retracted. F th more, the lever 10 cannot be moved to closed position except at substantially the instant the lever 8 reaches its open or retracted posltion.

Various changes in detail and arrangement may be made without departing from the spirit and scope of the invention, as defined in the accompanying claims.

I claim as my invention:

1. The combination with a pair of lovers, of an interlocking device therefor com rising. a movable member having cam sur aces to be engaged upon the movement of said levers, said movable member being provided with stop members for preventing the oper ation of either lever when the other lever is in its operative position, and a latch member for securing said movable member in one position.

2. The combination with a pair of levers having members movable therewith, of means for preventing the operation of either of said levers when the other is in its operative position, said means comprising a movable element having cam surfaces coacting with said members to control the position of said element, and a latch member for securing said element inlocking relation to one of said levers.

3. The combination with a air of levers having members movable t erewith, of means for preventing the operation of either of said levers when the other is in its opsecondary lever, a latch for holding the interlock member in said normal position, means carried by the primary lever for tripping the latch when the said lever is ad vanced and for moving the interlock member into released position with respect to the secondary lever when the primary lever is retracted, and means carried by the secondary lever for moving the secondary lever into locking relation with .respect to the primary lever when the secondary lever is advanced. A

5. The combination with a primary lever and a secondary lever, of an interlock member therefor provided with a locking portion for normally preventing advancement of the secondary lever and with camming surfaces, a latch for holding the interlocked member in said normal position, camming means carried by the primary lever for tripping the latch when the said lever is advanced and for moving the interlock member into released position with respect to the secondary lever when the primary lever is retracted, and camming means carried by the secondary lever for moving the interlock member into locking relation with respect to primarylever when the secondary lever is advanced.

6. The combination with a pair of levers, of an interlock device therefor comprising a movable locking member provided with stop members for preventing the advancement of either lever while the other lever is advanced, a latch for normally holding the locking member in locked relation-to the one lever, means effective during the movement of the other lever through a cycle, to trip the latch and to move the locking member to release position with respect to the first named lever, and means carried by the first named lever for moving the locking member into locking relation with the other lever when said first named lever is advanced.

8. The combination with a pair of levers, of an interlock device therefor comprising a locking member provided with stop members for preventing the advancement 'of either lever while the other lever is advanced, a latch for normally holding the locking member in locked relation to the one lever, means effective during the movement of the other lever through a cycle, to trip the latch and to move the locking memberto release position with respect to the first named lever,.

and means carried by the first named lever for moving the locking member into locking relation with the other lever when said first named lever isadvanced, the locking member moving to the said latched position, when the first mentioned lever is retracted.

In testimony whereof, I have hereunto subscribed my name this first day of June,

- J QSEPH D. WOOD. 

